Electrical power distribution systems, such as bus bars for example, are used in a variety of applications from smaller, low voltage, computer, electronic, and telecommunications systems to larger, higher voltage transportation systems such as trains and electric vehicles. Bus bars are generally comprised of one or more conductive layers, levels, or elements formed of a conductive material such as copper, brass, nickel, aluminum, and/or a suitable alloy for example, which may be plated, and one or more layers of dielectric or insulating material disposed proximate each conductive layer. The insulating material can be an epoxy, powder coating, and/or laminate thin film material which can be attached by a variety of methods including a heat press, for example, as is known in the art.
Referring to FIG. 1A, a prior art bus bar is shown having multiple conductive and insulating layers. The insulating layers are shown as sheets cut to approximately the shape of each alternating conductive layer. The open laminated construction shown in FIG. 1A does not provide for insulation of edges of the conductive elements, a general requirement for a bus bar to operate for its intended purpose.
Accordingly, several prior art methods of edge sealing have been developed including the pinched or molded/sealed construction shown in FIG. 1B. The bus bar of FIG. 1B provides insulating layers which do not account for corners, require additional material, cost, labor, and time to produce, and result in bus bars of increased size due to extension of the laminate at the pinched location.
Referring to FIGS. 1C and 1D, edge sealing can be provided by insertion of an insulating material such as a glass, including and not limited to flame resistant 4 (FR4) epoxy-woven glass. FIG. 1D shows a hardened epoxy resin at the edges The process of edge sealing with epoxy requires increased material and substantial labor to insert the epoxy and time to cure the epoxy and is therefore not a cost-effective method of bus bar manufacture.
Referring to FIG. 1E, a powder-coated multilayer bus bar is shown. Epoxy powder coating can be used to coat both the one or more surfaces of the conductive layers and the edges as is known in the art. However, powder coating is time-intensive, can require multiple applications, and results in insulating layers of uneven thickness, a significant disadvantage.
Moreover, the bus bars shown in FIG. 1A-E are of simple, alternating layer construction without secondary features such as flangeconductors or terminations, for example. Providing one or more insulating layers for bus bars, particularly those with multiple layers, having secondary features is particularly challenging using any of the above.
Accordingly, there is a need in the art for an efficient method of bus bar fabrication that provides for increased effectiveness of the dielectric insulation between conductive layers, particularly in multiple conductive layer applications, while reducing manufacturing cost and time.